CSP (Content Security Policy): a W3C draft spec that defines fine grained security policies for resource loading to mitigate the risk of injection attacks such as XSS. The policy per resource representation is defined in new header is Content-Security-Policy. Firefox and Chrome is experimenting in headers X-Content-Security-Policy and X-WebKit-CSP respectively. The spec also defines a report-only mode without browser enforcing the policy but sending violation reports to the server, which is helpful for gradually enforcing the right policy.